1. Field of the Invention
The invention relates to an apparatus for determining an output value according to a look up table and a method thereof, and more particularly, to an apparatus for determining an output value according to a simplified look up table and a method thereof.
2. Description of the Prior Art
Some specific mathematical functions, such as trigonometric function, exponential function, and logarithmic function, etc., are commonly-used in the operation of the electronic device, such as the electronic device for used in a communication system. It should be noted that the operation of such specific functions are complicated such that a complicated circuit is needed to perform such operations. One of the conventional methods is to build a look up table inside the electronic device to generate the expected value based on the sampling points stored in the look up table through interpolation, instead of performing the complicated math function directly. However, such specific mathematical functions are not linear functions. Therefore, a lot of sampling points needed to be stored in the look up table in order to meet the accuracy requirement of the electronic device. The memory size used for the look up table is large.